The national marriage rate has decreased to nearly half of what it was in 1970, according to the National Marriage Project, a nonpartisan research initiative based at the University of Virginia.

The national marriage rate has fallen from 76.5 marriages per 1,000 unmarried women 15 and older to 40.7 marriages in 2005, according to the group’s research.

The economy and the fact that more couples decide to cohabitate aid in the decline in the number of marriages, said Brad Wilcox, director of the National Marriage Project.

According to census figures, the number of cohabiting couples in 1970 was slightly more than 500,000, while in 2007 that number was more than 6.4 million.

The State of Our Unions Marriage in America 2009 (.pdf)

http://www.virginia.edu/marriageproject/